AD5302 Analog Devices, AD5302 Datasheet - Page 18

• Manufacturer Part Number: AD5302
• Manufacturer: Analog Devices

Specifications of AD5302

• Resolution (bits): 8bit
• Dac Update Rate: 167kSPS
• Dac Settling Time: 6µs
• Max Pos Supply (v): +5.5V
• Single-supply: Yes
• Dac Type: Voltage Out
• Dac Input Format: Ser,SPI

AD5302/AD5312/AD5322
APPLICATIONS INFORMATION
TYPICAL APPLICATION CIRCUIT
The AD5302/AD5312/AD5322 can be used with a wide range
of reference voltages, especially if the reference inputs are
configured to be unbuffered, in which case the devices offer full,
one-quadrant multiplying capability over a reference range of
0 V to V
be used with a fixed, precision reference voltage. Figure 38
shows a typical setup for the AD5302/AD5312/AD5322
when using an external reference. If the reference inputs are
unbuffered, the reference input range is from 0 V to V
the on-chip reference buffers are used, the reference range is
reduced. Suitable references for 5 V operation are the
and REF192 (2.5 V references). For 2.5 V operation, a suitable
external reference would be the REF191, a 2.048 V reference.
If an output range of 0 V to V
inputs are configured as unbuffered (for example, 0 V to 5 V),
the simplest solution is to connect the reference inputs to V
As this supply cannot be very accurate and can be noisy, the
AD5302/AD5312/AD5322 can be powered from the reference
voltage, for example, a 5 V reference such as the REF195, as
shown in Figure 39. The REF195 outputs a steady supply
voltage for the AD5302/AD5312/AD5322. The current required
from the REF195 is 300 μA supply current and approximately
30 μA into each reference input. This is with no load on the
DAC outputs. When the DAC outputs are loaded, the REF195
also needs to supply the current to the loads. The total current
required (with a 10 kΩ load on each output) is
The load regulation of the REF195 is typically 2 ppm/mA,
which results in an error of 2.7 ppm (13.5 μV) for the 1.36 mA
current drawn from it. This corresponds to a 0.0007 LSB error
at eight bits and a 0.011 LSB error at 12 bits.
360
Figure 38. AD5302/AD5312/AD5322 Using External Reference
AD780/REF192
WITH V
OR REF191 WITH
V
DD
EXT
REF
DD
μA
. More typically, the AD5302/AD5312/AD5322 can
= 2.5V
+
DD
V
2
OUT
= 5V
⎛
⎜
⎜
⎝
10
5
k
V
Ω
⎞
⎟
⎟
⎠
INTERFACE
=
SERIAL
. 1
1µF
36
DD
is required when the reference
mA
AD5302/AD5312/
V
V
SCLK
DIN
SYNC
REF
REF
V
DD
A
B
AD5322
= 2.5V to 5.5V
GND
V
DD
V
V
OUT
OUT
A
B
AD780
DD
, but if
DD
Rev. D | Page 18 of 24
.
BIPOLAR OPERATION USING THE
AD5302/AD5312/AD5322
The AD5302/AD5312/AD5322 are designed for single-supply
operation, but bipolar operation is also achievable using the
circuit shown in Figure 40. This circuit is configured to achieve
an output voltage range of –5 V < V
operation at the amplifier output is achievable using an
or OP295 as the output amplifier.
The output voltage for any input code can be calculated as
follows:
where:
D is the decimal equivalent of the code loaded to the DAC.
N is the DAC resolution.
V
If V
6V to 16V
REF
REF195
GND
REF
V
is the reference voltage input.
IN
V
V
Figure 40. Bipolar Operation Using the AD5302/AD5312/AD5322
V
OUT
OUT
OUT
= 5 V, R1 = R2 = 1 kΩ, and V
Figure 39. Using a REF195 as Power and Reference to the
6V to 16V
REF195
=
=
GND
V
(
⎡
⎢
⎣
IN
10
(
V
V
OUT
0.1µF
1µF
INTERFACE
×
REF
SERIAL
D
×
2 /
AD5302/AD5312/AD5322
D
10µF
N
2 /
0.1µF
1µF
)
INTERFACE
V
AD5302/AD5312/
SCLK
DIN
SYNC
R
REF
−
N
SERIAL
1
)
5
A/B
×
AD5322
V
V
DD
(
GND
V
R
DD
10µF
= 5V
1
+
V
10kΩ
V
V
V
AD5302/AD5312/
SCLK
DIN
SYNC
OUT
OUT
R1
DD
R
DD
REF
REF
2
A/B
= 5 V:
)
A
B
< +5 V. Rail-to-rail
AD5322
⎤
⎥
⎦
−
GND
V
10kΩ
R2
REF
V
V
OUT
OUT
×
+5V
–5V
(
A
R
B
/ 2
AD820/
OP295
R
AD820
1
)
±5V